Micron Technology (NASDAQ:MU) shares tumbled Friday after it said in a filing that a low-double-digit percentage of its worldwide revenue is at risk of being impacted.

“Several Micron customers, including mobile OEMs, are being contacted by certain Critical Information Infrastructure (“CII”) operators or representatives of the government in China concerning the future use of Micron products,” the company stated. MU is currently down over 2%.

It follows a Chinese ban on the sale of Micron’s chips to key domestic industries after a conclusion by the Cybersecurity Administration of China (CAC).

Micron’s revenue with companies headquartered in mainland China and Hong Kong represents around a quarter of its worldwide revenue and remains the main exposure.

The company now believes that roughly “half of that China HQ customer revenue, which equates to a low-double-digit percentage of Micron’s worldwide revenue, is now at risk of being impacted.”

“Micron is working to mitigate this impact over time and expects increased quarter-to-quarter revenue variability. Micron’s long-term goal is to retain its worldwide DRAM and NAND share,” the company concluded.

Earlier in the day, Micron said it was committed to China and that over the next few years, it plans to invest $603 million in its chip packaging facility in the city of Xian.

China’s cyberspace regulator has targeted the firm and previously said it had failed a network security review.